Scintillation Light Detectionvia CMOS image sensor

Lukas R. Hertrich

Conceptual Overview

Feasibility study of scintillator emission detection & imaging via CMOS image sensor

Why not photomultiplier tube (PMT) or silicon photomultiplier (SiPM)?

Accumulative imaging rather than single events

Further refinement possible if apparatus proves effective (lead shielding & pinhole-like aperture)

Lukas R. Hertrich

Scintillation

Scintillator material ionized by incoming radiation. Ionization along the particle track or per photoelectric effect, Compton scattering, and pair production for gamma radiation

Lower energy scintillation photons emitted as the bound electrons in ionized material deexcite

Example of detection of single incident particle event per photomultiplier tube

In contrast the apparatus is intended to accumulate scintillation from several events to produce an image

Lukas R. Hertrich

[5]

Apparatus OverviewLight-tight aluminium box lined with black felt to reduce reflections of scintillator emission

5 x 5 x 1 cm plastic BC-408 or BC-412scintillator

OV5642 camera module oriented towardsscintillator

Peltier circuit used to cool box, lower dark current (noise) in CMOS image sensor

DS18B20 sensor probe used to monitorbox temperature

Data exchange:Camera module <SPI/I2C> Arduino <Virtual RS-232> PC

Lukas R. Hertrich

Scintillator Specifications

Lukas R. Hertrich

Property BC-408 BC-412

Radiation detected 0.1 - 5.0 MeV 𝛄& all in BC-412

Fast neutrons, charged particles, cosmic rays, muons, protons, etc.

Light output % Anthracene

64 60

Rise time [ns] 0.9 1.0

Decay time [ns] 2.1 3.3

Pulse FWHM [ns] ~2.5 4.2

Light attenuation length to 1/e [cm]

210 210

Wavelength of max emission [nm]

425[3,4] 434[3,4]

[4]

Camera Overview5MP OV5642 CMOS image sensor with M12 mount 55° lens

I2C bus for sensor configuration &SPI for data exchange

Lukas R. Hertrich

[2]

Arduino & CameraInterfaceCommunication via SPI(Serial Peripheral Interface) andI2C (Inter-integrated circuit) bus

Lukas R. Hertrich

[1]

To do list & Schedule

Lukas R. Hertrich

● Saturday/Sunday : Reliable buffered serial communication between Arduino & PC/Laptop, signal characters to acknowledge reader/writer states

● Saturday/Sunday/Monday : Temperature probe testing

● Saturday/Sunday/Monday :Dark current (noise) vs. temperature plot with lens cap on or scintillator removed

● Tuesday - Thursday : Evaluation of image output with radioactive sources placed in front of or in dark box (e.g. Na22, Co60, Cs137)

● Time permitting : Image processing, sharpening, filtering near RGB values mapped to peak scintillator wavelengths

References

Lukas R. Hertrich

[1] Arducam mini cameras tutorial. Web, July 2018.

[2] ArduCam. ArduCAM-Mini-5MP-Plus OV5642 Camera Module 5MP SPI Camera User Guide, 1.0 edition, October 2016.

[3] Dan Bruton. Color science. Web, March 2014.

[4] Saint-Gobain Industrial Ceramics, Inc., 12345 Kinsman Road Newbury, Ohio 44065 USA. BC-400/BC-404/BC-408/BC-412/BC-416 Premium Plastic Scintillators, March 1998.

[5] PMT Illustration By KieranMaher at English Wikibooks - Transferred from en.wikibooks to Commons by Adrignola using CommonsHelper., Public Domain, https://commons.wikimedia.org/w/index.php?curid=8677937